Tissue ablation is a surgical technique that may be used to treat a variety of medical conditions, particularly when the treatment requires removing or destroying a target tissue. Medical conditions that can be treated by tissue ablation include, for example, benign prostatic hypertrophy, benign and malignant tumors, and destructive cardiac conductive pathways (such as ventricular tachycardia). Tissue ablation may also be used as part of common surgical procedures, for example, to remove or seal blood vessels.
Typically, ablation therapy involves heating a target tissue with a surgical instrument such as a needle or probe. The needle is coupled to an energy source that heats the needle, the target tissue, or both. Suitable energy sources include, for example, radio frequency (RF) energy, heated fluids, impedance heating, or any combination thereof. The needle may be presented to the target tissue during an open surgical procedure or through a minimally invasive surgical procedure.
The circulation of fluid from and/or around the electrode may be used for tissue irrigation, clearing ablated tissue, or cooling surrounding tissue during ablation therapy. Wet ablation is a type of ablation therapy performed with a wet electrode, which is a needle or probe capable of delivering both RF energy and a conductive fluid to the target tissue. The flow of the conductive fluid may assist in directing the ablation energy and cause a greater volume of tissue to be destroyed, effectively increasing therapy efficacy. Exemplary wet ablation apparatuses and therapy methods are described in U.S. patent application Ser. No. 11/787,211 by Thomas Skwarek et al., entitled, “USER INTERFACE FOR ABLATION THERAPY”, and issued on Nov. 1, 2011 as U.S. Pat. No. 8,048,069, which is incorporated herein by reference in its entirety.